Upon printing a plurality of copies of a given print by a conventional printing apparatus, a first method of storing print data received from, e.g., a host computer in a first storage unit, and printing the plurality of copies using the stored print data, and a second method of generating rendering image data such as a dot image or the like from the print data stored in the first storage unit, storing the rendering image data in a second storage unit, and printing the plurality of copies using the rendering image data stored in the second storage unit may be used.
The conventional printing apparatus supports one of the first and second methods, and even when both the methods are supported, a plurality of copies can only be printed using one method selected by the user.
In the printing apparatus that supports both the methods, the first and second methods often have different processing speeds depending on the contents of data to be printed, and the best performance cannot be obtained unless a method suitable for the data contents is selected. For example, when given data is to be printed, the first method can complete processing in a shorter period of time than the second method. However, when another data is to be printed, the second method can complete processing in a shorter period of time than the first method. In this case, only when a method that can complete processing in a shorter period of time is designated depending on data contents, the best performance can be obtained.
However, in such printing apparatus, it is difficult for the user to determine a method suitable for given data.
In a color printing apparatus having an engine with a density correction function, when a plurality of copies of a color document or the like are printed, a density correction process is done upon generating rendering image data. For this reason, in the first method that re-generates rendering image data for each copy, since density correction is done for each copy, the tincture never changes during the print process even when the density state of the engine has changed along with an elapse of time.
By contrast, in the second method, since a plurality of copies are printed by repetitively referring to the rendering image data generated at the beginning of the process, if the density state of the engine has changed along with an elapse of time after generation of the rendering image data, the chromaticness may change during the print processes of the plurality of copies.